sustainable living in the great white North

Posts Tagged ‘earthbag domes’

I’ve been terribly neglectful on the blog-front, I know. Busy, busy, hot, hot… you know- the life of a natural builder. Temperatures have been hitting between 30 and 35 degrees Celsius for a little over a month now, yesterday hit 40, and I admit to dragging my ass. I can get approximately half the work done in the same amount of time once temperatures reach about 25 so it’s slow going right now but it’s going.

I’m fitting lighter work in between bags. I’ve already had heat stroke a couple of times in the last week (in addition to falling off a wall- again, taking a nail through the foot, and bruising the right side of my body in an attempt to save myself from falling) so it seems a not bad idea.

Yesterday I worked on the arched nooks we built into the structure. You can see in the pictures below that I used rigid foam board (found, can’t remember where), chicken wire, and some staples. It came together relatively easily and I’ve applied the first plaster coat. I’m looking forward to seeing the finish product once we move forward with interior plaster. I think the spaces will be really neat.

Super ridiculously busy around here and not expecting things to let up until oh, I don’t know, winter but figured I should post some pictures of our progress. We’re a few weeks into the building season and things are moving quickly, if not as quickly as we’d (I’d?) like. I’m focusing on the master bedroom during the week while Shane’s at work and it’s coming along nicely. I have several new injuries that may prevent me from wearing any skirts in public this summer but that hasn’t slowed me down any. I really need to stop falling off walls though, or slashing myself with sharp objects, or not so sharp objects that just seem really sharp when applied with force…

Anyway, the domestead is further along than this already but these are the last pictures that we took. 🙂

We’ve heard a lot about UV damage to polypropylene bags. I was interested in seeing for myself just exactly how badly they degrade so I set up a little experiment. I filled a bag with gravel and stuck it aside. Unfortunately I soon after forgot about it so I’m not sure exactly how long it takes to progress to this level of damage but one thing is for certain- this bag is toast.

I dragged a single finger through a patch in the bag that was splitting and you can see how badly it held up. So- protect your bags as you build. Anything from a light plaster to paint will work, just so long as the bag is protected from sunlight. And just a note- you do have to get on top of it pretty quickly. While not an experiment per se, I did think I had more time to get a light plaster up than I did. While the bags didn’t degrade like this one, they did loosen up slightly making plastering a bit more difficult. The smoother and tighter the bags, the easier the plaster goes up. Lesson learned.

I haven’t had much time for updates recently. Between planting trees, amending soil, building and planting the gardens, and site preparation things have been a leeet’le busy around here. We did finally get started building on Saturday though, so the season is officially ON and we have nothing to slow us down but mother nature herself.

We’ve been asked a number of times what kind of mix we’re using in our bags. We’ve gone with a stabilized clay-soil/gravel mixture. The clay-soil is from our property, we were fortunate enough that the previous owners had dug giant holes on the property (to bury garbage if you can believe it) and they left massive hills of clay next to the holes. We get cheap gravel reject from a nearby pit and we use the smallest amount of cement to stabilize the mix.

sifting station

The first step is sifting the clay. It’s a bit of a time consuming process (although Shane’s got it down to a bit of an art) but necessary for the most consistent results. We’ve set up a salvaged expanded metal screen between two barrels. We set the wheelbarrow beneath the screen, toss shovelfuls of clay-soil onto the screen, and sift away. Shane can fill a wheelbarrow in about ten minutes- I won’t say how long it takes me.

work station

The work station is where all of the mixing happens. In this photo you can see the pile of gravel reject, the wheelbarrows full of sifted clay, the cement mixer, and the buckets that we use to haul the mix. You can also see the cats who’ve taken to using my gravel pile as a litter box- not impressive. I’m thinking of putting down some snow fence just to keep them off the pile. It’s either that or I’m shipping them off to the city. There’s nothing quite like the smell of ammonia to make a long day seem even longer.

very little cement

I use an old bucket to measure my quantities. I’m going for a 70:30 gravel:clay ratio so I use three and a half buckets of gravel and one and a half buckets of clay-soil. Every new load of gravel is slightly different, as is the clay content in the soil when we switch to a new part of the hill, so I constantly ‘re-check’ the texture of my mixes. I’ve handled enough mixes to be able to judge by touch whether I have the right ratio. The amount of cement added is only very small. You can see in this photo how high the cement content is compared to the other ingredients.

gravel & cement first

I load my gravel and cement into the mixer first, give the cement a little toss with my hand to premix it, and then add water and start the mixer. I like the gravel and cement fully mixed before I start adding clay. Clay prefers to stick to itself and I’ve found there’s way less clumping if I toss it in once the gravel is prepared, and the cement is better distributed.

hand mixing

I reach in and pull the mix from the back of the mixer while it’s turning just to make sure no dry materials are sitting at the back. No OH&S on this site I’m afraid. I add a very little bit more water if required at this stage. It’s important not to over-saturate your mix though, so only add a small amount at a time in between checking the texture.

checking mix

A good mix will form a ball when squeezed in your hand but will break if squeezed too hard. If it continues to compress under pressure, there’s too much water. You don’t want an overly wet mix- it’s insane to try tamping and takes forever to dry. Our mix tamps really well and forms a solid brick in no time.

one completed mix

One load gives me four buckets of mix. It actually takes six buckets (about 175 lbs) to fill a single bag so I’m only getting two bags for every three mixes that I prepare. I have (several times) tried to load more into the mixer but, like many of my attempted shortcuts, it’s not a time saver. I get the most consistent results from a smaller load and consistency is imperative for the best earthbag bricks. When Shane and I are working together, we can produce about twenty six bags (thirty nine mixes) a day. I do about half that working alone.

So that’s our mix process. As always, I recommend you do your own testing. Clay-soil differs at every location and the gravel reject you use may have a different clay or sand content. Experiment a little before you settle on the mix that is just right for you. Happy building!

I was flipping through one of our notebooks yesterday and came across a list that Shane and I compiled while building our first earthbag structure, the sauna, in 2009. Some of it is obvious, and other ‘tips’ were decided only after repeated injury or mistakes along the way. I had to laugh at our total disregard for some of the warnings that we failed to heed this year as well, in an effort to ‘do more’. Anyway, here it is, our lessons learned. Maybe it’ll save someone some trouble.

*Nail down the barbed wire to keep it from moving, fence staples work really well.

*Rinse the cement mixer immediately after use, and at least once during the day, for easier cleaning.

*Mix gravel and cement first, dry, and then add clay- so that the clay doesn’t just stick to itself.

*Tamp the sides of tubes/bags, not just the top.

*Lift with your knees.

*Always feel the mix with your bare hands, soil-clay and gravel may differ slightly from mix to mix. Wear gloves in between to avoid rubbing the skin right off your hands.

*Trust your instincts and communicate (e.g if the mix feels wrong, even if you’re not the one mixing, mention it).

*Cut tubes a little long.

*Fill tubes straight, and twist along arc. Don’t try to fill them ‘on a curve’.

*Don’t start late in season. We started the sauna in September, had plans to leave town for a couple of weeks, and ended up working straight into snow.

*Use good weather and daylight for building, bad weather and evenings for prep and planning.

*Don’t make plans/commitments during the building season and be prepared to be a weather watcher.

*A good cob mix that we found was 1.5 sand, 1 clay, .5 manure, and straw.

*Don’t try to mix too much cob at once- it will not save time.

*And finally- if you’re not both committed to the project, don’t even bother.

Not a bad list. If you can stick to it, you can avoid a fair amount of frustration and injury. I didn’t, even though the lessons were hard won. I almost always carry more than I’m comfortable with. Shane works off the property so during the week it’s just me and I’ve gone with the argument that I can get more done if I just suck it up. It’s true- I get a lot done. But I’ve injured myself a lot and sometimes quite seriously.

On that note, if you’re bleeding- take a break. Honestly, I felt like superwoman some days- working through the pain and the blood- but if you injure yourself seriously enough without breaking, you’ll probably injure yourself again. And while we’re on the subject of breaks, a person can only work seven days a week for so many months before you’re ready to bite the heads off kittens. Or maybe that’s just me…

I also didn’t get a lot of meal prep done ahead of time. There’s nothing quite like working your ass off for 10 hours straight just to come inside and start preparing a meal to make you feel bitter. At least that was my experience. This year, I’ll start freezing meals for the building season in February.

The tip on scavenging- seriously a good idea. You never know what you’re going to need. One really good find for us were grader blades. They make excellent supports for above windows if you’re going with a straight line instead of arches. We had no idea what we were going to use them for when we brought them home but they’ve been beautiful to work with.

And one that didn’t make the list but has got to be the funniest lesson learned this year- measure your doors carefully! We took into account our own builds, and what we thought was ‘reasonable’, and totally didn’t factor in things we might want to move into the house- like a couch. The only way any larger furniture is getting in there is if we drop it in from the top before the roof is on. Ya- not going to be happen. Luckily we’d planned on building most of our furniture into the house but good to know…

It seems we’re always racing time, or the weather, or some other factor completely outside of our sphere of influence. It’s a typical October in Alberta, which means we’ve had our first (second and third) snowfall. It hasn’t snowed in a few days now but we haven’t hit above freezing temperatures either and the acreage looks like a veritable winter wonderland. It’s beautiful really, but not entirely conducive to outdoor work- at least not until we’ve more fully acclimatized.

We’ve just about finished plastering the buildings for winter. A few half decent days and we should be done. And we need to get some above freezing weather (forecast for next week) to finish the last row of bags at the front entrance. Other than that, we need to finish temporarily roofing the structures and fit the windows so that we can work indoors through the winter.

We have plans for a rocket mass heater in the living room, as well as a greenhouse sunspace, and have cabinets to build, a bathtub to form, and pipes for greywater reuse to lay out. We’ll also need a part wall in the kitchen. I’m sure there’s more that I’m forgetting. One of these days I’ll get around to writing out a handy ‘to-do’ list but in the meantime…

We also have plenty of outdoor work to complete, including moving tons of earth (quite literally) to build up the garden around the kitchen and living room areas. Because of the sheer mass of the buildings, and the materials we’re using (primarily the earth beneath our feet), the zone immediately around the building on the south side will be different than elsewhere on the property and we hope to be able to grow plants that would not otherwise do well on the property. The ‘surround garden’ will also further shelter the building from some of our more extreme temperatures.

Add to which there are the day to day tasks and preparing for winter- clean up (long overdue), preparing the garage and shop for indoor work, reorganizing materials, covering the last of the raised bed gardens, and so on. (And this doesn’t even speak to the commitments that we have off the property…) It could be overwhelming but strangely it’s not. I think I’ve finally found my ground in this pioneer lifestyle and have come to appreciate the work, even the sheer amount of it. Maybe it’s because I can’t think of another time in my life when the work that I was doing felt so right. And maybe it’s partly due to the fact that my body has had time to heal from the abuse heaped upon it during the building season. Either way, I’m feeling good about it.

Some of you may be wondering where we’ve been these last few weeks. We’ve decided to abandon the earthbag building in favour of digging a hole in the side of a hill. Holes are notoriously cozy, animals have favoured them for years as comfortable living spaces, and we think this will get us into a natural building that much sooner. So we’ve been busy dig, dig, digging.

Okay, I jest. We’ve been hard at work getting the kitchen and living room domes to level so that we can put in the second floors and cover them for winter. That done, we’re working on the front entrance which I expect we’ll be done by end of weekend. Then we can work on the floors.

We’ll be using lengths of the telephone poles that we were fortunate enough to have donated as centre columns and we’ve purchased some inexpensive round wood that will converge at the centre, something like a wheel configuration. From there we’ll nail down our floor and then tarp the whole thing for winter, while we work inside.

I’ll post photos of the building once the floor is up, with any luck in the next week or so.

We’re also working on the plaster and it’s coming along, if not “nicely” well enough. And we’ve continued to collect materials, the best find of which was a woodstove for $75. It’s in beautiful condition and I can’t wait to try it out.

Well friends, thanks to those of who’ve been kind enough to search us out and ask where we’re at. As always, we appreciate the support and community! And on that note, I’m off to plaster…